Survival in Women After Diagnosis of Lung Cancer

Abstract

To the Editor: The I-ELCAP investigators reported the results of a cross-sectional analysis of their series of 16 925 healthy smokers who underwent CT screening. This analysis indicated a higher prevalence of screen-detected lung cancers in women than in men. A prospective analysis indicated increased survival in women with lung cancer compared with men who had lung cancer. The authors interpret their findings as evidence that women are more susceptible to the carcinogenic effect of tobacco smoke on the lung. There are alternative explanations for these results. The clinical relevance of the pulmonary nodules detected via CT screening has not been confirmed, so these findings may represent overdiagnosis of lesions that would not evolve into clinically important life-threatening tumors. The prevalence of detection of such clinically irrelevant lesions might be higher in women than in men, either because of actual differences in their prevalence or because of characteristics of the screening test. Evidence from observational studies does not support a conclusion that CT screening for lung cancer reduces mortality. Alternatively, the higher survival of women with lung cancer may result from a tendency for lung cancers to be, on average, less aggressive in women than in men. If so, then men who started smoking at the same time as women and who smoked as heavily may have been more likely to be diagnosed earlier than women with identical smoking histories; if this occurred, they would have been preferentially excluded from the cross-sectional analysis, leading to an artifactual underrepresentation. Overall, the evidence from epidemiological studies indicates that women are not more susceptible to smokinginduced lung cancer than men.